Angles whose measures add up to 90°.

Two complementary adjacent angles form a right angle.

### Examples

In this figure, angles *A* and *B* are complementary, since the sum of their measures is 90°.

Since these angles are adjacent, they form a right angle.

In the figure below, where a pair of parallel lines intersects another pair of parallel lines, angles *A* and *B* are also complementary, even though they are not adjacent. In fact, a translation can be applied to make the vertices of angle *A* and angle *B* coincide and form a right angle.